#include "agent_auth.h"

#include "core/crypto/crypto_core.h"
#include "core/os/os.h"
#include "core/string/print_string.h"

AgentAuth *AgentAuth::singleton = nullptr;

AgentAuth::AgentAuth() {
	singleton = this;
}

AgentAuth::~AgentAuth() {
	singleton = nullptr;
}

void AgentAuth::_bind_methods() {
	ClassDB::bind_method(D_METHOD("register_agent", "name", "permissions"), &AgentAuth::register_agent, DEFVAL(PERM_ALL));
	ClassDB::bind_method(D_METHOD("unregister_agent", "token"), &AgentAuth::unregister_agent);
	ClassDB::bind_method(D_METHOD("validate_token", "token"), &AgentAuth::validate_token);
	ClassDB::bind_method(D_METHOD("check_permission", "token", "perm"), &AgentAuth::check_permission);
	ClassDB::bind_method(D_METHOD("get_agents"), &AgentAuth::get_agents);
	ClassDB::bind_method(D_METHOD("get_audit_log", "count"), &AgentAuth::get_audit_log, DEFVAL(100));
	ClassDB::bind_method(D_METHOD("get_agent_info", "token"), &AgentAuth::get_agent_info);
	ClassDB::bind_method(D_METHOD("set_max_requests_per_minute", "max"), &AgentAuth::set_max_requests_per_minute);

	BIND_ENUM_CONSTANT(PERM_READ);
	BIND_ENUM_CONSTANT(PERM_WRITE);
	BIND_ENUM_CONSTANT(PERM_EXECUTE);
	BIND_ENUM_CONSTANT(PERM_ALL);
}

Dictionary AgentAuth::register_agent(const String &p_name, uint32_t p_permissions) {
	MutexLock lock(auth_mutex);

	AgentSession session;
	session.agent_id = vformat("agent_%d", OS::get_singleton()->get_ticks_msec());
	session.agent_name = p_name;
	session.token = _generate_token();
	session.permissions = p_permissions;
	session.connected_at = OS::get_singleton()->get_ticks_msec();
	session.last_activity = session.connected_at;

	sessions[session.token] = session;

	Dictionary result;
	result["agent_id"] = session.agent_id;
	result["token"] = session.token;
	result["permissions"] = session.permissions;

	print_line(vformat("AgentAuth: Registered agent '%s' (id: %s)", p_name, session.agent_id));
	return result;
}

void AgentAuth::unregister_agent(const String &p_token) {
	MutexLock lock(auth_mutex);
	if (sessions.has(p_token)) {
		print_line(vformat("AgentAuth: Unregistered agent '%s'", sessions[p_token].agent_name));
		sessions.erase(p_token);
	}
}

bool AgentAuth::validate_token(const String &p_token) {
	MutexLock lock(auth_mutex);
	return sessions.has(p_token);
}

bool AgentAuth::check_permission(const String &p_token, Permission p_perm) {
	MutexLock lock(auth_mutex);
	if (!sessions.has(p_token)) {
		return false;
	}
	return (sessions[p_token].permissions & (uint32_t)p_perm) != 0;
}

void AgentAuth::record_activity(const String &p_token, const String &p_method, const String &p_path, int p_status) {
	MutexLock lock(auth_mutex);

	// Update session activity.
	if (sessions.has(p_token)) {
		sessions[p_token].last_activity = OS::get_singleton()->get_ticks_msec();
		sessions[p_token].request_count++;
	}

	// Add to audit log.
	AuditEntry entry;
	entry.timestamp_msec = OS::get_singleton()->get_ticks_msec();
	entry.agent_id = sessions.has(p_token) ? sessions[p_token].agent_id : "unknown";
	entry.method = p_method;
	entry.path = p_path;
	entry.status_code = p_status;
	audit_log.push_back(entry);

	if (audit_log.size() > MAX_AUDIT) {
		audit_log.remove_at(0);
	}
}

bool AgentAuth::check_rate_limit(const String &p_token) {
	MutexLock lock(auth_mutex);
	if (!sessions.has(p_token)) {
		return false;
	}

	// Simple rate limiting: check requests in the last minute.
	// For a proper implementation, use a sliding window counter.
	// This simplified version just checks total requests.
	const AgentSession &session = sessions[p_token];
	uint64_t elapsed = OS::get_singleton()->get_ticks_msec() - session.connected_at;
	if (elapsed == 0) {
		return true;
	}

	float minutes = (float)elapsed / 60000.0f;
	float rate = (float)session.request_count / MAX(minutes, 0.01f);

	return rate <= (float)max_requests_per_minute;
}

Array AgentAuth::get_agents() const {
	Array result;
	for (const KeyValue<String, AgentSession> &kv : sessions) {
		Dictionary dict;
		dict["agent_id"] = kv.value.agent_id;
		dict["name"] = kv.value.agent_name;
		dict["permissions"] = kv.value.permissions;
		dict["connected_at"] = kv.value.connected_at;
		dict["last_activity"] = kv.value.last_activity;
		dict["request_count"] = kv.value.request_count;
		result.push_back(dict);
	}
	return result;
}

Array AgentAuth::get_audit_log(int p_count) const {
	Array result;
	int start = MAX(0, audit_log.size() - p_count);
	for (int i = start; i < audit_log.size(); i++) {
		Dictionary dict;
		dict["timestamp_msec"] = audit_log[i].timestamp_msec;
		dict["agent_id"] = audit_log[i].agent_id;
		dict["method"] = audit_log[i].method;
		dict["path"] = audit_log[i].path;
		dict["status_code"] = audit_log[i].status_code;
		result.push_back(dict);
	}
	return result;
}

Dictionary AgentAuth::get_agent_info(const String &p_token) const {
	Dictionary dict;
	if (sessions.has(p_token)) {
		const AgentSession &s = sessions[p_token];
		dict["agent_id"] = s.agent_id;
		dict["name"] = s.agent_name;
		dict["permissions"] = s.permissions;
		dict["connected_at"] = s.connected_at;
		dict["last_activity"] = s.last_activity;
		dict["request_count"] = s.request_count;
	}
	return dict;
}

String AgentAuth::_generate_token() {
	// Generate a random hex token.
	uint8_t bytes[32];
	for (int i = 0; i < 32; i++) {
		bytes[i] = (uint8_t)(Math::rand() % 256);
	}

	String token;
	for (int i = 0; i < 32; i++) {
		token += vformat("%02x", bytes[i]);
	}
	return "agent_" + token;
}